fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: usize = n.trim().parse().unwrap();
    let a = (0..n).map(|_| {
            let mut temp = String::new();
            std::io::stdin().read_line(&mut temp).ok();
            let temp = temp.trim();
            temp.chars().collect::<Vec<_>>()
        })
        .collect::<Vec<_>>();
    let mut m = String::new();
    std::io::stdin().read_line(&mut m).ok();
    let m: usize = m.trim().parse().unwrap();
    let b = (0..m).map(|_| {
            let mut temp = String::new();
            std::io::stdin().read_line(&mut temp).ok();
            let temp = temp.trim();
            temp.chars().collect::<Vec<_>>()
        })
        .collect::<Vec<_>>();

    let length = a.iter().map(|v| v.len()).sum::<usize>();
    for i in 0..n {
        let mut lefts = String::new();
        let mut rights = String::new();
        for &c in a[i].iter() { lefts.push(c); }
        while lefts.len() < length || rights.len() < length {
            if lefts.len() == rights.len() { break; }
            if lefts.len() < rights.len() {
                let idx = lefts.len();
                let val = rights.chars().nth(idx).unwrap();
                if let Some(word) = a.iter().filter(|&v| v[0] == val).nth(0) {
                    word.iter().for_each(|&c| lefts.push(c));
                } else {
                    break;
                }
            } else {
                let idx = rights.len();
                let val = lefts.chars().nth(idx).unwrap();
                if let Some(word) = b.iter().filter(|&v| v[0] == val).nth(0) {
                    word.iter().for_each(|&c| rights.push(c));
                } else {
                    break;
                }
            }
        }
        if lefts.len() == length && rights.len() == length {
            println!("{}", lefts);
            return;
        }
    }
    println!("-1");
}